Asking questions with a yes/no answer can be the starting point of a good discussions, but only if there is a follow-up question that calls for explanation or substantiation. Otherwise, yes/no questions tend to be conversations-stoppers. By the same token, discussions can stall if the instructor's questions are overly leading, i.e., if there is clearly an answer the instructor wants, and the trustmypaper review students' task is simply to guess it, rather than to think for himself.